Efforts will continue to be directed towards isolation and characterization of both drug-resistant and temperature-sensitive lines of A. albopictus cells. Hybrids will be obtained between suitably marked parental cell lines. Of special interest will be the properties of a hybrid formed by fusion of a CPE-susceptible (Sindbis virus-induced CPE) and a CPE-resistant cell. Considerable attention will also be given to the careful determination of the nutritional requirements of the A. albopictus cell line.